"She eats very slowly and deliberately and finishes everything on her plate," Cohen said. "At a birthday party she is usually the last one off the table from eating pizza or birthday cake, and she always asks for seconds."

A parent might not recognize that a child is obese, Dolgoff said, because the child may look like all of the other kids in the neighborhood, or even slightly thinner.

"In the '70s, our kids were much thinner," Dolgoff said.

The not-so-secret recipe for childhood obesity is by now familiar: fast-food plus processed food, add in some preservatives, some sugar; and mix with video games, television, computers and our dependency on cars. All that cooks up to an epidemic, with one in three kids across the country now overweight or obese.

Battling the Bulge in Nashville

Just outside Nashville, Tenn., second-grader Nicholas Reeves is also battling the bulge. At 8 years old, he already weighs 117 pounds.

"He's just hungry all the time," mom,Angel Reeves said. "He can finish eating a meal and then five minutes later he's coming in the kitchen saying, 'I'm hungry again, I'm hungry again.'"

Reeves said Nick is a very active child who loves to play basketball. But his weight has already impaired his health. Nick had to have his tonsils removed because the thickness of his neck was causing sleep apnea.

"He actually weighs more than his 13-year-old brother, so he is teased by him," Reeves said.

Beyond the emotional toll of taunting and teasing, the stakes for obese children can be as high as for obese grownups. Dolgoff ticked off some of the more serious health risks.

"High blood pressure, high cholesterol, type 2 diabetes, heart attack, stroke," she said. "Being overweight during childhood decreases life span. You just want to get your overweight child healthy as soon as possible so you can maximize their life span."

Childhood Obesity: Can Programs Help?

Both Nicholas Reeves and Samantha Stevens embarked on an effort that their families and doctors hoped would change their habits, and therefore their lives. The children enlisted in two different programs designed for obese kids.

"I'm just hoping that like a boat, we can change her course," Cohen said of daughter Samantha.

At the start of their programs, both Samantha and Nick were weighed and their heights were measured. The figures were used to calculate Body Mass Index, or BMI, the common measure doctors use to track obesity.

Samantha's BMI percentile was dangerously high.

"As you can see, she is well above the highest line, so her BMI is above the 97th percentile," Dolgoff said. "It's not high enough to be above the 99th percentile, so she's not considered morbidly obese, but she is in the obese category. ... She is at risk for medical illness because of her weight."

Nick's BMI percentile was up there as well.

"He is greater than the 95th percentile, and the No. 1 thing that he is at risk for developing as a young adult is type 2 diabetes," Plemmons said. "That's the No. 1 thing that we see directly related to obesity. He is also at risk for heart attacks and heart disease. ... He's at risk for low self-esteem, he's at risk for mental health issues."

The doctors explained an important distinction between treating childhood and adult obesity. Overweight adults need to lose weight. For overweight kids, however, gaining weight is normal because they're still growing.

The goal for overweight kids is to get them just to stay at one weight for a while, a weight their bodies can grow into until it becomes more normal for their height and age.

"Do you think we've brought [Samantha] here in time to turn things around and get her healthy?" Cohen asked.

Dolgoff sees patients one-on-one and also runs an online program used by kids in 46 states across the country.

Plemmons opened the pediatric weight clinic at Vanderbilt six years ago in response to rising obesity numbers. Since then, the clinic has treated more than 500 children.

"There aren't many clinics around the country that sort of specialize in this area," Plemmons said.

'Red Light, Green Light, Eat Right'

The challenge, of course, is complex and enormous. How do you teach a child who is not even old enough to read, to watch what he or she eats?

Dolgoff has developed a kid-friendly program called "Red Light, Green Light, Eat Right."

"Kids know green is go, yellow is slow, red is stop, they understand that," Dolgoff said. "Using that to relate to food just makes it easy for them. They get it. ...

"I took every food and divided them into either red light, yellow light and green light categories. I made it fun for the kids. Green light foods are go. Yellow light foods are slow. And red light foods are uh-oh. ... You want it to be kid friendly, and that kind of stuff helps."

The main idea is to get kids, and their parents, to think before they eat.

Dolgoff took Samantha and her mom to the local grocery store to show them how the system works.

No foods are off-limits because the program isn't a diet, Dolgoff said. But, foods high in fat, sugar and calories are considered "red light" foods; in other words, "treats" that the child is only allowed to eat twice a week.

"It doesn't mean that you can never eat them, but we have to stop and think, 'Do I want to make this choice?'" Dolgoff said. "Sometimes, you're going to get a temper tantrum. That's just the way it goes. But, after a while, the kids learn sometimes they can have those unhealthy foods and sometimes they can't."

"Green light" foods are high in protein, fiber and nutrients. This includes lean meats, whole grains and fruits and veggies. One key is involving the child in the selection process at the store and making the experience fun, Dolgoff said.

Dolgoff also taught Cohen, Samantha's mom, how to read nutrition labels and how to make sense of tricky packaging. She shows her how to look for low-calorie and low-fat dessert options so Samantha doesn't feel deprived.

"It seemed fun and doable and I'm very excited," Cohen said. "I can't wait to get going. It's going to be challenging but I think overall it will work out. ... You just don't think to analyze food labels the way she taught me to do today. We will certainly be paying a lot more attention in the supermarket."

Childhood Obesity: What's Going on at Home?

At the weight clinic in Tennessee, nutrition is also a big emphasis. The team at the clinic planned to create a road map specific to Nick's needs. But before making any suggestions, they first had to figure out what was going on at home.

"What is dinner usually like?" dietitian Amy Freedman said.

"It's usually a meat and two vegetables, and then we fix him macaroni and cheese every night because that's the only thing he'll eat," Reeves said.

"When it comes to that stuff I'll eat the whole pan," said Nick.

"And then some kind of roll or corn bread," said Reeves.

Amy asked about the weekends.

"Usually, it's a fast-food place," Reeves said. "His favorite place is Wendy's, and he would usually get..."

Plemmons asked Nick questions about other habits. Did he have a TV in his bedroom? Yes. Play Station 2? Yes. Nintendo? Yes. Xbox? Yes.

Plemmons asked if mother and son took any walks together.

"No," Nick said.

"He played basketball this past fall and he started wheezing and coughing," Reeves said.

Plemmons said Nick was just young enough that his condition was still reversible.

"The older you are when you struggle with it, the more predictive it's going to be life-long," Plemmons said. "Right about his age right now, 50 percent of the kids that I see that are in this state are going to stay that way. So I think 50-50 is pretty good odds."

Next, Nick met with a physical therapist. At the end of the appointment, he was given a list of individualized goals.

"We really tried to stress with Nicholas today primarily nutrition goals," Plemmons said. "The one goal I hope that he keeps is cutting back on the Gatorade. I think that's where a lot of his extra calories are sneaking in."

If Nick could maintain his current weight over the next several months, while also growing taller, his BMI would drop and that would mean success.

Childhood Obesity and Self-Esteem

Back in New York, Lori Cohen was putting Dolgoff's program to the test, introducing Samantha to new "green light" foods.
As Cohen saw it, helping Samantha to lose weight was about more than just the physical. She too had been heavy as a little girl, she said, and suffered years of hurtful teasing.

"I don't want her getting hurt, I don't want her to lose that self-esteem," Cohen said. "I want her to go and reach the stars."

Two weeks into the program, they saw results: Samantha had lost one pound.

But it wasn't all good news. Dolgoff had results from Samantha's physical exam. They showed abnormally high levels of cholesterol.

For Cohen, it was further confirmation that she was doing the right thing.

To take the program a step further, Samantha and her mom joined Dolgoff and her daughter for a "Mommy & Me" workout with a fitness trainer.

At her next check-up two weeks later, Samantha had maintained her weight and grown a quarter of an inch.

"The important thing for kids is maintaining the weight while also growing, so she is doing great," Dolgoff said.

Putting Obesity Programs to the Test

Back in Tennessee, Nick was working on his new healthy goals. He played basketball with his brother while, back in the kitchen, his mom helped him with portion control.

"We show Nicholas how to look for a serving size," said Reeves, placing snacks in single servings into plastic bags.

Reeves was introducing vegetables to snack on. "He has learned that mac and cheese is not a vegetable," she said.

And every other day, Reeves and Nicholas went on walk-jogs around the neighborhood.

"We're training for a 5K in September," Reeves said.

"This is the fourth week that we did it," Nick said. "And it gets easier every time."

"Nightline" checked in with Cohen and Samantha to see how things were going nearly six months into their program.

"She understands if food is a green, it's healthy, if it's a yellow, not so good, and if it's a red that's a once-in-a-while thing," Cohen said.

Cohen showed us some of the changes she had made in the kitchen, which was stocked with butter spread, low-cal vitamin water and after-school snacks of fruit and cheese.

"Broccoli was a hit, spinach was a hit," Cohen said. "Tonight we're going to try artichokes. And we're going to try some pre-seasoned salmon burgers, because she asked for hamburgers tonight."

A big lesson for Cohen has been learning how to set boundaries.

"Second helpings are a no," she said. "I tell her that it's not healthy, 'How would you like some fruit, how would you like a banana?'"

But is it really feasible for children so young to stick to such new routines ?

In two months, Nick's BMI had actually become slightly worse: He gained five pounds while not growing a single inch taller.

"I think this points out that even with a supportive family and tools that we give families, it really is hard to lose weight," Plemmons said.

Nick's mother said they would continue the battle at home. "I know he is more healthy with the exercise and the food choices that he's making and his attitude. ... I'm a very proud mom," Reeves said. "Very proud mom."

In six months, Samantha's BMI was down.

"She is out of the obese category, she's in the 93rd percentile," Dolgoff said. "She did almost lose three pounds, and that's equivalent to an adult losing 15 to 20 pounds."

"It's fantastic," Cohen said. "It's exactly what I wanted to have happen."